Antisway trailer hitch

ABSTRACT

The trailer hitch inhibits sidesway of a trailer by use of a transversely extending track tube connected at its opposite ends to the rear of the towing vehicle. A drawbar hinged to the trailer and pivoted to the traction vehicle includes a pivoted guide sleeve movable on rollers laterally along the tube for transmitting towing power between the towing and towed vehicles. A forward portion of the drawbar extends to permit lateral movement of the guide sleeve on the track tube. The drawbar has a swivel coupling permitting relative rolling movement between the vehicles. A rear portion of the drawbar has a load equalizer including a coil spring operable in conjunction with the trailer jack to vary the distribution of the axle loads between the trailer and towing vehicle.

ilnited States Patent [72] Inventor Charles F. Holt Rte. 2, Box 220,Corvallis, Oreg. 97330 [2|] Appl. No. 835,146 [22] Filed June 20, 1969[45] Patented Aug. 24, 1971 [54] ANTISWAY TRAILER HITCH 11 Claims, 6Drawing 5.

52 us. (31. 280/406 A, 280/447, 280/489 [51] lint. Cl 862d 53/00 [50]Field 01 Search 280/406, 406 A, 447, 489

[56] References Cited UNITED STATES PATENTS 2,828,144 3/1958 l-losmer280/483 3,400,948 9/1968 Matson 280/406 3,434,735 3/1969 Bernard...3,353,842 11/1967 Lewis Primary ExaminerLe0 Friaglia Atmmey-Buckhor,Blore, Klarquist and Sparkman ABSTRACT: The trailer hitch inhibitssidesway of a trailer by use of a transversely extending track tubeconnected at its opposite ends to the rear of the towing vehicle. Adrawbar hinged to the trailer and pivoted to the traction vehicleincludes a pivoted guide sleeve movable on rollers laterally along thetube for transmitting towing power between the towing and towedvehicles. A forward portion of the drawbar extends to permit lateralmovement of the guide sleeve on the track tube. The drawbar has a swivelcoupling permitting relative rolling movement between the vehicles. Arear portion of the drawbar has a load equalizer including a coil springoperable in conjunction with the trailer jack to vary the distributionof the axle loads between the trailer and towing vehicle.

PATENTED AUG24|97| 3,601,427

SHEET 1 0F 2 FIG. 5

' 96 I lol CHARLES F. HOLT INVENTOI? BY BUG/(HORN, BLORE, KLAROU/ST aSPAR/(MAN ATTORNEYS ANTISWAY TRAILER HITCH BACKGROUND or THEINVENTION 1. Field of the Invention The present invention relates to atrailer hitch. It more particularly relates to a trailer hitch forpreventing sidesway and equalizing the axle loads on the towed andtowing vehicles.

2. Description of the Prior Art The prior art includes a trailer hitchutilizing a laterally extending rail to inhibit sidesway. However, suchrail is of open channel construction which permits dirt, mud and grit tocollect and thereby inhibit lateral tracking movement of the trailerdrawbar along the rail, thereby seriously impairing the effectivenessand life of the hitch.

Prior hitches of the foregoing type are also longitudinally rigid and donot permit relative rolling movement between the tractor and trailerabout a longitudinal axis except for limited rolling movement at theball-and-socket connection between the hitch and trailer tongue.However, forces at this point are undesirable for they tend to separatethe ball and socket. In such prior hitch, leaf springs in conjunctionwith the ball-andsocket connection further inhibit relative rollingmovement between the tractor and trailer and. therefore increase thetorsional stress on the hitch.

The prior tracking-type hitch of the foregoing type has provision forequalizing the axle loads between tractor and trailer. However, suchmeans does not operate satisfactorily under heavy loads. Therefore usingvehicles using a hitch must be loaded with care to prevent overloading;

SUMMARY OF THE INVENTION The present invention overcomes thedeficiencies of the prior art track-type hitch through the provisionof atrack-type hitch' having 1 a track assembly of closedconstructioncapable of functioning in the presence of mudand dirt, (2-)a built- .in swivel coupling permitting unrestrictedrolling movementbetween tractor and trailer without the use of a dangerousball-and-socket connection, and (3) load. equalizer. means operable withthe trailer jack to distribute trailer loads between the axles of thetrailer and tractor vehicles.

Primary objects of the hitch assembly of the inventionare t0.

l. inhibit trailer sidesway through the use of a tracking hitchassembly; 2. provide free tracking movement of, the hitchdrawbaruninhibited by mud or'dirt; 3. permit unrestricted twisting movement.between tractor and trailer through a swivel coupling in thehitchdrawbar;-

4. vary the distribution of axle loads between tractor and trailer bymeans of the hitch assembly;

5. distribute axle loads through use of the trailer jack in conjunctionwith the hitch assembly;

6. permit rolling, pitching, and yawing movements between tractor andtrailer at three longitudinally separated points along the hitchdrawbar;

7. provide a safe yet inexpensive hitch construction which can bemanufactured using primarily readily available standard parts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 4 is a vertical sectional viewtaken along the line of 4- 4 of FIG. 2 on a larger scale than FIG. 2;

FIG. 5 is a vertical sectional view taken along the line 5-5 of FIG. 2on a scale larger than FIG. 2 and slightly smaller than FIG. 4; and

FIG. 6 is a sectional view taken along the line 6-6 of FIG. 4.

DETAILED DESCRIPTION With reference to the drawings, FIG. 1 discloses anautomobile A towing a trailer T using a track-type hitch assembly 10 inaccordance with the invention.

Referring more particularly to FIGS. 2 and 3, hitch assembly 10 includesa drawbar assembly 12 and a track assembly 14. Track assembly 14includes a tubular track member 16 extending transversely at the rear ofthe traction vehicle A. A smaller diameter tube 18 extends through tube16 to strengthen the track member, although such smaller tube isoptional. First and second connector means including connector arms 20,21, connect the opposite ends of track member 16 to the rear of theautomobile, preferably at the bumper brackets, using fasteners 22, 23.

Drawbar means 12 includes a rear forked portion 26 joined to trailer Tat a third, hinged connection 28 for movement about a transverse hingeaxis 30. The forward end of fork portion 26 is joined at a fourth,swivel connection 32 to an intermediate drawbar portion 34. A forwarddrawbar portion 36 telescopes within intermediate portion 34 to vary thelength of the drawbar as required. Forward portion 36 of the drawbar isconnected to the frame 38 of the traction vehicle by a pivot pin 40enabling pivoting of the drawbar assembly about a vertical pivot axis41.

Forward drawbar member 36 is rectangular in cross section and slideswithin a rectangular tube portion 42 of the intermediate drawbar section34. Rectangular tube 42 joins one side of an open rectangular sleevemounting bracket 44. A sectionof round tubing 46 projects rearwardlyfrom a bracket 44 to form a continuation of the drawbar to swivelcoupling 32. Angular metal straps 47, 48 and a bottom plate 49 reinforcethe connection.

A generally cylindrical tracking sleeve member 52 is mounted byvertically aligned pivot pins 54, 55 within bracket 44 for pivotalmovement about the vertical axis of the pins, extending through drawbarmeans 12. Tubular member 16 extends-through tracking sleeve 52. Sleevemember 52 provides lateral tracking movement of drawbar 12 axially alongtrack member 16 as permitted by the extensible forward portion 36 of thedrawbar assembly.

With reference to FIG. 4, tracking sleeve 52 is made up of four sleevesections 57, 58, 59, 60 in surrounding but spaced relationship to trackmember 16. Each sleeve section has a pair of radial flanges 62, 63spaced from corresponding flanges of' adjacent sleeve sections. Rollermeans, including four rollers 70 are rotatably mounted by pins 65 withinthe slots between adjacent flanges 62, 63 at each end of the trackingsleeve. Thus a total of eight rollers support the tracking sleeve andthus the drawbar on the track tube 16. The radically innermost peripheryof the eight rollers extend inwardly of the four sleeve sections andengage the cylindrical outer surface of track tube 16 to maintain thetrack tube in centered spaced relationship to the sleeve sections and topermit rolling movement of the tracking sleeve along the track tube.

Each of the eight rollers 70 is made up of a pair of sealed ball'bearingmembers 74, press-fitted into an outer metal rim '76: The four rollersat each end of sleeve 52 are symmetrically arranged about thecircumference of the track member at'positions offset from thehorizontal and vertical planes through the axis' of such' member. Withthis arrangement together with the sealed roller bearings, closedtubular track and tracking sleeve, the tracking assembly is shieldedfrom dirt and other foreign matter, and will not freeze" in theirpresence.

Tube section 46 of the drawbar joins fork arms 80, 81 of fork section 26at swivel coupling 32. As shown best in FIGS. 2 and 5, swivel connection32 includes an extra heavy-walled pipe section 83 fixed within pipesection 46. Pipe section 83 extends rearwardly through another pipesection 85 to which fork arms 80, 81 are fixed. Pipe section 83 remainsrotatable with respect to pipe section 85 to form bearing surface forswiveling movement of pipe section 85 relative to pipe section 46. Alocking ring 86 retains pipe section 83 within pipe section 85. Thus theintermediate and forward portions of the drawbar assembly can swivelwith respect to the rearward forked section of the assembly while thedrawbar assembly remains longitudinally rigid.

Referring to FIGS. 2 and 3, fork arms 80, 81 of the drawbar divergerearwardly and are connected to the trailer at hinge connection 28. Therear ends of fork arms 80, 81 form knuckles 88 which are joined byremovable hinge pins 89, 90 to hinge brackets 91 on a lower portion ofan angle member 92. Of course, a single long rod (not shown) extendingthrough both knuckles and brackets could be substituted for the twohinge pins. Angle member 92 is fixed to the underside of a forwardlyprojecting tongue 94 of trailer T. Thus to remove the hitch assemblyfrom the trailer, hinge pins pins 89, 90 are simply removed from hingebrackets 91 and knuckles Trailer tongue 94 has the usual trailer jack 96just rearwardly of the conventional socket portion 98 for a conven'tional ball-and-socket hitch connection (not shown) which is not used.As shown in FIG. 5, trailer jack 96 includes a crank handle 100 andvertical jack shift 101 including a threaded portion 102 threadedthrough a nut 1 03 on tongue 94.

In accordance with the present invention the hitch includes an equalizerassembly operable in conjunction with the trailer jack to distribute theload imposed by the trailer between the rear axle of the automobile andthe trailer axle. This is done by raising and lowering the hitchassembly and thus the trailer tongue and rear of the automobile usingthe trailer jack. For this purpose jack shaft 101 extends throughtrailer tongue 94 and terminates at its lower end in an enlarged cap104. The jack shaft slides within a vertical pipe section 106 uponoperation of the jack handle. However, the shaft is prevented fromprotruding from the lower end of the pipe section 106 by a pin 107. Thispin is removed when the jack is used in the normal way without thehitch. Pipe section 106 terminates at its upper end in a horizontalplate 108 which, in the upwardly retracted position of the jack as shownin FIG. 5, abuts the underside of trailer tongue 94. The lower end ofpipe section 106 extends through a central opening 109 of a plate 110which extends between the opposite fork arms 80, 81 of the drawbar.

A coil spring 112 extends between upper plate 108 and drawbar plate 110.This spring maintains vertical separation between the trailer tongue 94and the drawbar portion therebeneath and prevents collapse of thetrailer about its hinge connection 28.

Because the drawbar is longitudinally rigid and has no hinge connectionwith the traction vehicle about a horizontal axis, any tendency to raisethe front end of the trailer also tends to lift the drawbar and rear endof the traction vehicle, thereby tending to unload the rear wheels ofthe traction vehicle.

With the trailer jack and equalizer elements arranged as shown in FIG.with cap 104 engaging pin 107, any effort to screw jackshaft 101downwardly further below trailer tongue 94 tends to push pipe section106 downwardly through opening 109 of drawbar plate 110, thereby forcingplate 108 to compress downwardly also as indicated in dashed lines andtending to compress coil'spring 112 between the two plates 108 and 110.

However, spring 112 resists compression, and therefore the downwardextension of jackshaft below trailer tongue 94 elevates the tongue aboveplate 108. Elevation of tongue 94 raises hinge connection 28, thereforealso raising the drawbar and unloading the rear axle of towing vehicle.A. This shifts part of the load from such rear axle to the traileraxle.

Upward movement of the jackshaft has the reverse effect, shifting aportion of the load from the trailer axle to the rear axle of the towingvehicle.

The foregoing hitch construction has been found to reduce sideswayconsiderably in drawing relatively large, heavy trailer with alightweight towing vehicle. The extensible nature of the forward drawbarportion 36 enables the drawbar, including guide sleeve 52, to tracktransversely of the vehicle along tubular track 16 and thereby shift thepoint at which pulling forces are transmitted to the towing vehicle tocounter any tendency of the trailer to sway.

The illustrated hitch assembly eliminates the usual dangerousball-and-socket connection between tractor and trailer while allowingmaximum rolling at the swivel connection 32. At the same time thetracking principle employed by the hitch assembly operates in thepresence of dirt and mud. A further advantage of the hitch assembly isits simplicity of manufacture, using almost entirely conventionalstructural members, thereby minimizing its cost of manufacture. Finallythe load equalizer feature operable in conjunction with a conventionaltrailer hitch enables safe and proper distribution of the axle loadsbetween tractor and trailer. All of the above features combine toprovide a hitch which increases the safety of towing highway trailers.

Having shown and described a preferred embodiment illustrative of theprinciples of my invention, it should be apparent to those skilled inthe art that the same permits of modification in arrangement and detail.My intention is not to be limited by the illustrated embodiment, but toinclude within the scope of my invention all such modifications andequivalent constructions.

1 claim:

1. In a trailer hitch assembly:

a track assembly including an elongated track member and first andsecond connector means for connecting the opposite ends of said trackmember to a traction vehicle at laterally opposite sides of said vehiclein a manner so that Said track member extends transversely of saidvehicle,

a drawbar assembly including trailer drawbar means, third connectormeans for connecting one end of said drawbar means to a trailer vehicle,and fourth connector means for connecting the opposite end of saiddrawbar means to said traction vehicle at a point laterally between thepoints of connection of said first and second connector means andforwardly of said track member,

said track member having a closed cylindrical outer surface,

a tracking sleeve means pivoted to said drawbar means inten'nediate theopposite ends thereof for pivotal movement about an upright axisextending through said drawbar means,

said track member extending through said tracking sleeve means,

said tracking sleeve means including a plurality of roller meansrotatably carried by said sleeve means and adapted for rollingengagement with the outer surface of said track member at spacedpositions circumferentially of said track member in a manner permittingfree rolling movement of said sleeve means along said track member,

said drawbar means extensible in length between said fourth connectormeans and said sleeve means to permit pivoting movement of said drawbarmeans about said fourth connector means.

2. A hitch assembly according to claim 1 wherein each said roller meansincludes a series of ball bearing members.

3. A hitch assembly according to claim 1 wherein said roller meansinclude at least four roller member spaced symmetrically about saidtrack member and in rolling engagement with said track member atpositions offset with respect to the horizontal and vertical planesthrough the axis of said track member.

4. Apparatus according to claim 1 wherein said sleeve means comprises agenerally cylindrical sleeve member defined by a series of separatecurved sleeve sections interconnected by said roller means, said rollermeans, said roller means extending inwardly of the inner diameter ofsaid sleeve member.

5. A hitch assembly according to claim 1 wherein said drawbar meansincludes swivel means between said third connector means and said sleevemeans for permitting relative rotation between the portion of saiddrawbar means rearwardly of said swivel means and the portion of saiddrawbar means forwardly of said swivel means about the longitudinalcenterline of said drawbar means.

6. A hitch assembly according to claim 1 wherein said third connectormeans includes means for providing a hinge connection of said drawbarmeans with a forward portion of a trailer vehicle about a transversehinge axis, and adjustable load equalizer means, said load equalizermeans including compression spring means adapted to extend between saiddrawbar means and a portion of said trailer vehicle forwardly of saidhinge axis to exert a separating force therebetween, and means foroperatively connecting said spring means with a trailer jack on saidforward trailer portion in a manner such that operation of said jacktends to vary the compression of said spring means and thereby changethe elevation of the forward end of the trailer vehicle.

7. Apparatus according to claim 6 wherein said means for connecting saidspring means with a trailer jack includes a vertical tube meanssurrounding an extensible vertical shaft portion of said trailer jack,said compression spring means comprising a coil spring surrounding saidvertical sleeve member, the lower end of said spring means abutting saiddrawbar means, the lower end of said spring means abutting an enlargedportion of said vertical tube means, the lower end of said vertical tubemeans including an abutment member limiting the downward movement ofsaid jackshaft within said vertical tube means and means providing anopening through said drawbar means permitting downward movement of saidjackshaft and vertical tube means through said drawbar opening, wherebydownward movement of said jackshaft tends to compress said coil springto elevate the forward portion of said trailer vehicle.

8. Apparatus according to claim 6 including swivel means between saidequalizer means and said sleeve means permitting relative swivelingmovement between forward and rear portions of said drawbar means alongitudinal axis extending between said vehicles.

9. A trailer hitch assembly comprising:

drawbar means including first connector means for hingedly connecting arear portion of said drawbar means to a forward portion of a trailingvehicle for movement about a transverse hinge axis and second connectormeans for connecting a forward portion of said drawbar means to a towingvehicle,

said drawbar means between said first and second connector means beinglongitudinally rigid,

adjustable load equalizer means including compression spring meansadapted to extend between said drawbar means and a portion of thetrailing vehicle forwardly of said hinge axis to exert a separatingforce between said drawbar means and said trailer,

said equalizer means including means operatively connected to saidspring means and operable with a trailer jack on said forward trailerportion in a manner such that operation of said jack tends to vary thecompression of said spring means and thereby change the elevation of theforward end of the trailer vehicle, said hinge axis and thus saiddrawbar means and rear end of the towing vehicle to vary the loaddistribution between the rear axle of the towing vehicle and the axle ofsaid trailer vehicle.

10. Apparatus according to claim 9 wherein said means for connectingsaid spring means with a trailer jack includes a vertical tube meanssurrounding an extensible vertical shaft portion of said trailer jack,said compression spring means comprising a coil spring surrounding saidvertical tube means, the

lower end of said spring means abutting said drawbar means, the upperend of said spring means abutting an enlarged portion of said verticaltube means, said vertical tube means including an abutment memberlimiting the downward movement of said jackshaft within said tube means,and means providing an opening through said drawbar means permittingdownward movement of said jackshaft and vertical tube means through saiddrawbar opening, whereby downward movement of said jackshaft tends tocompress said coil spring to elevate the forward portion of said trailervehicle.

11. Apparatus according to claim 9 including swivel means on saiddrawbar means positioned between said load equalizer means and saidsecond connector means for providing relative rolling movement betweenforward and rear portions of said drawbar means about a longitudinalcenterline of said drawbar means.

1. In a trailer hitch assembly: a track assembly including an elongatedtrack member and first and second connector means for connecting theopposite ends of said track member to a traction vehicle at laterallyopposite sides of said vehicle in a manner so that said track memberextends transversely of said vehicle, a drawbar assembly includingtrailer drawbar means, third connector means for connecting one end ofsaid drawbar means to a trailer vehicle, and fourth connector means forconnecting the opposite end of said drawbar means to said tractionvehicle at a point laterally between the points of connection of saidfirst and second connector means and forwardly of said track member,said track member having a closed cylindrical outer surface, a trackingsleeve means pivoted to said drawbar means intermediate the oppositeends thereof for pivotal movement about an upright axis extendingthrough said drawbar means, said track member extending through saidtracking sleeve means, said tracking sleeve means including a pluralityof roller means rotatably carried by said sleeve means and adapted forrolling engagement with the outer surface of said track member at spacedpositions circumferentially of said track member in a manner permittingfree rolling movement of said sleeve means along said track member, saiddrawbar means extensible in length between said fourth connector meansand said sleeve means to permit pivoting movement of said drawbar meansabout said fourth connector means.
 2. A hitch assembly according toclaim 1 wherein each said roller means includes a series of ball bearingmembers.
 3. A hitch assembly according to claim 1 wherein said rollermeans include at least four roller member spaced symmetrically aboutsaid track member and in rolling engagement with said track member atpositions offset with respect to the horizontal and vertical planesthrough the axis of said track member.
 4. Apparatus according to claim 1wherein said sleeve means comprises a generally cylindrical sleevemember defined by a series of separate curved sleeve sectionsinterconnected by said roller means, said roller means, said rollermeans extending inwardly of the inner diameter of said sleeve member. 5.A hitch assembly according to claim 1 wherein said drawbar meansincludes swivel means between said third connector means and said sleevemeans for permitting relative rotation between the portion of saiddrawbar means rearwardly of said swivel means and the portion of saiddrawbar means forwardly of said swivel means about the longitudinalcenterline of said drawbar means.
 6. A hitch assembly according to claim1 wherein said third connector means includes means for providing ahinge connection of said drawbar means with a forward portion of atrailer vehicle about a transverse hinge axis, and adjustable loadequalizer means, said load equalizer means including compression springmeans adapted to extend between said drawbar means and a portion of saidtrailer vehicle forwardly of said hinge axis to exert a separating forcetherebetween, and means for operatively connecting said spring meanswith a trailer jack on said forward trailer portion in a manner suchthat operation of said jack tends to vary the compression of said springmeans and thereby change the elevation of the forward end of the trailervehicle.
 7. Apparatus according to claim 6 wherein said means forconnecting said spring means with a trailer jack includes a verticaltube means surrounding an extensible vertical shaft portion of saidtrailer jack, said compression spring means comprising a coil springsurrounding said vertical sleeve member, the lower end of said springmeans abutting said drawbar means, the lower end of said spring meansabutting an enlarged portion of said vertical tube means, the lower endof said vertical tube means including an abutment member limiting thedownward movement of said jackshaft within said vertical tube means andmeans providing an opening through said drawbar means permittingdownward movement of said jackshaft and vertical tube means through saiddrawbar opening, whereby downward movement of said jackshaft tends tocompress said coil spring to elevate the forward portion of said trailervehicle.
 8. Apparatus according to claim 6 including swivel meansbetween said equalizer means and said sleeve means permitting relativeswiveling movement between forward and rear portions of said drawbarmeans a longitudinal axis extending between said vehicles.
 9. A trailerhitch assembly comprising: drawbar means including first connector meansfor hingedly connecting a rear portion of said drawbar means to aforward portion of a trailing vehicle for movement about a transversehinge axis and second connector means for connecting a forward portionof said drawbar means to a towing vehicle, said drawbar means betweensaid first and second connector means being longitudinally rigid,adjustable load equalizer means including compression spring meansadapted to extend between said drawbar means and a portion of thetrailing vehicle forwardly of said hinge axis to exert a separaTingforce between said drawbar means and said trailer, said equalizer meansincluding means operatively connected to said spring means and operablewith a trailer jack on said forward trailer portion in a manner suchthat operation of said jack tends to vary the compression of said springmeans and thereby change the elevation of the forward end of the trailervehicle, said hinge axis and thus said drawbar means and rear end of thetowing vehicle to vary the load distribution between the rear axle ofthe towing vehicle and the axle of said trailer vehicle.
 10. Apparatusaccording to claim 9 wherein said means for connecting said spring meanswith a trailer jack includes a vertical tube means surrounding anextensible vertical shaft portion of said trailer jack, said compressionspring means comprising a coil spring surrounding said vertical tubemeans, the lower end of said spring means abutting said drawbar means,the upper end of said spring means abutting an enlarged portion of saidvertical tube means, said vertical tube means including an abutmentmember limiting the downward movement of said jackshaft within said tubemeans, and means providing an opening through said drawbar meanspermitting downward movement of said jackshaft and vertical tube meansthrough said drawbar opening, whereby downward movement of saidjackshaft tends to compress said coil spring to elevate the forwardportion of said trailer vehicle.
 11. Apparatus according to claim 9including swivel means on said drawbar means positioned between saidload equalizer means and said second connector means for providingrelative rolling movement between forward and rear portions of saiddrawbar means about a longitudinal centerline of said drawbar means.